A/N: Welcome to the panic room! This is just meant to be a fun little story, nothing to take super seriously, so I hope you all enjoy. It's nine chapters and I plan to update once a week, so long as the editing goes as planned.

Also, a little house-keeping: I don't think this will be an issue but, if by any chance this premise seems familiar, I did first use this plot over on ao3 for a completely different pairing a few years back. I'm fairly doubtful many people share the two pairings in common, but don't want to risk someone having read the other one and then believing this is plagiarism. (Okay, maybe it's a bit of self-plagiarism, but this isn't academia so I'm not counting that rule.)

Anyway, with that done: please enjoy!

welcome to the panic room

The first thing Rick Castle's hit with as he rouses slowly into consciousness is an ache in his head, one that evolves pretty quickly from a dull throb to an intense pounding. The second is the sudden blinding awareness of the sun; his eyes are screwed shut, but the brightness behind them tells him that it is, in fact, morning and he is facing the window. He doesn't remember leaving the blinds open, but it wouldn't be the first time.

Remaining as still as possible lessens the pounding of his head but does nothing to stop the daylight from paining his sensitive eyes even through the protection of his closed lids, and so he chances angering the already full-blown headache in order to thwart the beginnings of another one. Carefully, eyes still closed, he flips his body and nearly sighs with relief as the darkness surrounds him.

With the sun now beating down on his back, he gives himself one, two, maybe three minutes (probably closer to ten, but who's counting) and then he forces his eyes open. Blinking is a challenge but he gets through it, and then he stretches his stiffened legs, digging his feet into the mattress.

God, this is rough. Last night's Castle, the bastard, did absolutely nothing to help this morning's Castle.

Swinging his legs over the side of the bed, he swipes roughly at his eyes and lets out a low groan. There's a travel sized tube of ibuprofen and a bottle of water on the bedside table and he fights the urge to fist pump in celebration, if only because the jerky motion would most certainly rattle his already throbbing brain. He exhales his appreciation instead, popping two of them into his mouth.

Today's going to be painful, but it's not all bad.

Nikki Heat is officially on the market, out in the world for all of his adoring fans to enjoy; and for new fans to enjoy, too, of course. After two years of shadowing Beckett, weaseling his way into her bubble (and nearly getting himself thrown out of it on several occasions), and forming an actual friendship with the detective (she may argue against this point, but they're friends, dare he say best friends, and she can't convince him otherwise), the book is actually done.

It's like giving birth. At least, it's what he assumes giving birth feels like. His book baby is now welcomed into the world.

A wide smile curls at his mouth and he covers his face with his hands.

Last night's Nikki Heat launch party went about as well as it possibly could, which is really all he could've asked for.

And Becket... well, she was probably the highlight.

The moment she walked in the party all dolled up, that stunning blue dress clinging to her body so perfectly it may as well have been made just for her, he was done for. He's not surprised Paula was all over him within seconds, going on about how it's no surprise he finds her special and something about how he doesn't want to leave the real Nikki Heat any more than he wants to leave the fictional one.

Though Paula had a point (he's not done with Nikki Heat and he's sure as hell not done with Beckett), seeing Beckett there, a smile on her face as she read the dedication, it made the entire night that much more—

He's hit with a startling third realization: he's alone.

His bed is empty, save for himself and the suit jacket he was wearing last night that's now crumpled near the end, dangling over the edge. There are no signs of anything being out of place, which on a normal morning would be nothing out of the ordinary. This would be good, it is good, kind of, except there's also no sign of Beckett which, his gut tells him—for reasons he's unsure of and still trying to work through—is bad.

Applying pressure to the bridge of his nose, Castle stands (slowly, squeezing his eyes shut in a futile attempt to dull his headache), wanders into the bathroom to brush his teeth (he breathes into his cupped palms and the combination of morning breath and lingering booze is not pleasant), all the while wracking his brain, willing it to work through the throbbing.

They enjoy the book launch, he actually manages to spend the majority of his time not mingling (Paula harps on him for this) but with Beckett, he wakes up alone with a feeling that he shouldn't have. And now here he is, trying to fill in the missing pieces.

Things he knows for certain: he and the group of them from the 12th, the boys and Beckett, went out for a late night Remy's and some drinks following the book launch. Espo was the first one to buy him a drink, which he remembers because he'd made a teasing quip about taking him out to dinner first.

Glancing at the clock, he sighs. It's a little after 9:00, which he's not sure is too early to be awake considering the state he's in or if it's too late, despite the state he's in. He wonders idly how the boys are faring, if they're dutifully continuing their actual jobs and considerably less hungover than he is, or if they're sporting a hangover much like the one he's enjoying on this lovely morning. Either way, he knows they're already at the precinct.

He knows he's going to be more than a little late, but right now he's just grateful he's more prone to headaches than vomiting.

As he's throwing on a pair of jeans, things start flooding back in short bursts.

The latter half of the book launch, the after-hours group celebration, him handing Beckett a drink and her small but appreciative smile, followed immediately by the thrumming of his heart at the sight of it. That's right; Castle remembers switching from beer to liquor (a rookie move, of which he knows better, but they had the good whiskey and he knew he couldn't resist, knew he was ruined for the rest of the night right then), but Beckett stuck to gin and tonics.

Were there shots? He thinks there were shots, which would also account for why his skull feels abnormally shitty right now. Yes, there were definitely shots. He doesn't remember who ordered them, but process of elimination leaves him believing it was either him or Espo.

Castle can party with the best of them; he's had many years of practice, especially in his early days. He can hold his alcohol extremely well but sometimes, he'll admit, he still has a tendency to go a bit overboard (on rare occasions, those deemed justified, and he'd say last night was definitely one of them) and then this happens—dizzying blanks in his memory.

The whole thing strikes him as odd, really, because it's never due to the fact that he's blackout drunk. No, in the moment he's always pleasantly buzzed and high off of the adrenaline, completely in control of his faculties, even if he is a little louder and a lot more boisterous. He thinks of it like those moments when you're totally aware that you're laughing louder than anyone else but you've got such a rush that you don't care enough to tone it down. Everything's there, memories and complete awareness tucked safely where they should be—until he goes to sleep, and then it's as if it's just wiped retroactively, the excess alcohol pouring in like rain and washing spots away.

In the past, though, he hasn't felt this... strange. The blanks have always consisted of his own embarrassing actions—which he always learns at a later date through secondhand stories from his friends—and the loss of those particular memories never weigh quite so heavily. This feels different, like there's more.

A flash of Beckett's hand on his bicep, her voice echoing sentiments like yes, he deserves to let go a bit in celebration but yes, he should probably also take it down a notch, drink some water. He doesn't think she had any shots, but maybe she did; he doesn't remember.

9:27am.

He decides to climb back into his bed for ten more minutes, on top of the blankets so he doesn't get too comfortable, and then he'll get ready to head to the precinct. That's reasonable; at least he's dressed.

It only takes a few seconds after he settles back, head on the pillows and eyes closed, for more images to rush in. Except these aren't from the launch party, no, they're from afterwards, and he immediately shoots right back into a sitting position.

Fuck, his head.

Beckett's laughter ringing in his ears, her hand clasped in his own as they traipse through the hallway. This hallway. His building's hallway. He vaguely remembers asking her, back at the party, if she wanted to get out of there; book releases are thrilling but the crowds of well-wishers and the press can be overwhelming. Yes, even for him when sometimes, just sometimes, he doesn't really want to spend hours on end plastering on his poster-boy smile.

And he knows for Beckett, who never signed up for the press or the flashing lights, it's equally as—probably more so, if he's honest—intense for her.

The decline is on the tip of her tongue, he can see it in the way her mouth opens and she hesitates. He's about to try to convince her, just once, and then let it go if she holds onto her stance; tonight's already given him more time than he'd expected to spend with her.

"I could go for a burger," is what she says instead, eyes soft, and he thinks he's imagining the brief hint of a sparkle as she watches his face light up.

Yes, right, he knows this; they went to Remy's. The boys came too, as he's already deciphered; or remembered, really. But then...

"I gotta call it a night, guys," Ryan says first, two drinks and a burger down. "Congrats again, Castle."

Ryan left first. Espo hung around for a bit longer, he remembers, eyeing the two of them for a little bit before he was the next one to leave. He joked something about needing his beauty sleep and then he gave Castle a look as he stood from their booth. A don't do anything stupid look, if he remembers correctly—and hell, who knows if he is at this point—and now he's just trying to figure out if he heeded that warning.

So he and Beckett were the last two at Remy's and... nothing. Blank.

Groaning, he closes his eyes, wills that tiny fragment of memory to come back, of the two of them in his apartment's hallway, wills it to get less fuzzy. It's all he's got, the two of them in the hallway, some laughter, Beckett's little close-mouthed smile as he—

They were in his living room. Or sitting at the island, maybe. Definitely in the loft.

That's where more holes are then, the memories hazier. It's like they were cut and edited, slapped together out of order and made into jagged puzzle pieces that don't fit quite right.

"Oh, no. No, no, no," he moans quietly to himself, digging the heel of his palm into his eyes.

No. Right?

There's the two of them kissing, his hands on her waist, her delicate fingers caressing his face. Those eyes of hers, big and beautiful and so bold—have they always been that bright?—staring right back at him, so close. He's on the edge of bed and she's in front of him, pulling at the fabric of his shirt? Pulling him closer? He can't tell.

"Oh Rick, are you sleeping with her?"

His response is quick, "No!"

"Well what the hell are you waiting for? Go get it out of your system and then come down to the office and sign the damn contract, okay?"

He digs the heel of his palm into his eyes. But they didn't... he didn't actually take Paula's advice, did he?

(Not that he'd ever be able to get her out of his system, and he's positive if they ever did sleep together it'd have the opposite effect, leave him yearning for more of her.)

Castle slams his eyes closed as tightly as he can, tries to... rearrange or replay or something, anything that'll fill him in on what happened last night before he loses what's left of his mind. He's trying to work his memories like a damn editing software and it's not working and he think he might just combust.

He reverts to what he would do when he was a kid and he wanted to switch the images in his dreams or try to get back into one after waking up; just blink a few times, eyes squeezed tightly on each blink, and concentrate. He doesn't remember if it ever actually worked or not.

It's not working now, though, which is frustrating and does nothing to help the increasing race of his heart. Because everything he can remember, foggy and incomplete as it is, points to sleeping with Beckett. But he couldn't have slept with Beckett and this is for two reasons: one, because given their current relationship level he's not entirely sure he wouldn't have just been kneed in a very delicate place before it could happen; and two, because he'd remember that, right? Choppy memories be damned, if he'd had sex with Beckett he'd sure as hell remember.

Yeah, he'd remember.

But what if he did and he doesn't.

He absolutely does not want to be that guy, and he wants nothing less than being that guy with her. Because if they slept together he knows damn sure that he knew exactly what he was doing last night, and she'd know that, wouldn't go along otherwise; and the reverse is true, he'd do nothing if she wasn't completely on board, if she wasn't aware of what she was doing.

His nonchalance now would make it seem like he's just brushing her, and what they did, off. It'd make him seem like an asshole, and the thought alone makes him nauseous. He's spent this long trying to get her to believe he's not just the stuck up, playboy of a man she's seen plastered all over Page Six.

Right now it's looking very much like something felt off when he woke up alone because he wasn't alone when he went to bed. Beckett being nowhere in sight left a sinking feeling in the pit of his stomach because she spent the night with him and is now gone. The thought of her leaving in the middle of the night is almost worse than not remembering anything at all.

Unless his brain is making all of this up, completely tricking him in his alcohol-induced stupor to believe something that's false. Untrue. A fabrication of his own mind.

Okay, Castle, think.

It'd be much easier if he could just text her, settle this maybe-situation quickly, but that's a whole other undertaking he doesn't even want to think about. Hey, Beckett, by any chance did we have sex last night? No, yeah, absolutely not. Do not pass go, do not collect $200.

Things pointing towards sex with Beckett: (1) these memories, though their reliability is questionable; (2) the pills and water on his bedside table—that's 100% a Beckett move because he never thinks ahead to take care of his hungover self, which means that at some point she was in this room; (3) ... there doesn't seem to be a third thing, but one and two are pretty compelling on their own.

Twisting his head, he looks at the clock again. 9:57am. Shit. He hadn't meant to spend this long trying to figure out... all of this. Reaching over, he grabs his phone from where it's charging (did he plug that in last night? He feels a little, or a lot, like he's going insane) and squints at the too-bright screen.

There's a text from Beckett, sent about an hour and a half ago.

His heart catches in his throat as he clicks on her message.

Body between Bleeker and Crosby. If you're not too hungover, it looks right up your street.

That's it. Huh.

Okay.

Things pointing towards no sex with Beckett: (1) nothing seems amiss with her texts. She doesn't generally use emojis, ever, so the lack of any is no indication that she's upset with him; (2) he was totally dressed upon waking up. This one's a weaker point, because of course he could've gotten dressed after, but it's... well, it's something. He's grasping at straws here.

The most telling, though: surely, if they did sleep together and then something caused her to sneak out in the middle of the night (of course, one thing he has yet to entertain is the fact that she still had work this morning, so surely that could've been an innocent reason to duck out... but without a note?), she wouldn't be sending him a text at all, let alone one about a body drop and insinuating he should go to the scene.

Right?

He laughs a little; Beckett would be so impressed with his mental lists right now. He's the writer, sure, but she's more organized than she lets on, makes lists about most things.

Shaking his head, he does everything he can to put it all to the side and focus on... literally anything else. The flashes of Beckett's face so close to his and the feel of her lips sliding across his own will just have to wait. They won't go away—now that they're here he thinks, a bit regretfully because he doesn't know what they mean, they'll stick around.

But he's practically a master at putting all of his feelings for her on the back-burner, kept in hidden, far away sections of his mind. He's been doing it practically since he met her, most definitely for at least six months now. He can do it for a few more hours, or however long it takes to figure it all out.

I'm on my way.

Beckett doesn't say a thing.

Actually, no, that's a lie; she says many things.

She asks him how he's feeling and makes a joke about how he's getting older, can't handle his alcohol like he used to; she offers a small but genuine smile when he thanks her again for coming to the launch (this is for him to gage any ill feelings, though it doesn't go as planned because he doesn't sense anything); she talks to him about the body drop and the crime scene since he didn't arrive in time to meet them there, instead re-routing right to the precinct.

She greets him with a tired upturn of her lips and a nod of acceptance when he offers to grab coffee from the breakroom, but she doesn't say a damn thing about last night.

He tries to subtly feel for details.

"Don't take this as an admission of defeat or anything, but I think I had one too many last night," he says with an exaggerated groan. Espo and Ryan echo the sentiment from where they're standing, huddled around Espo's desk, and though it's not the response he's looking for, he's grateful he's not the only one feeling the effects.

The boys don't look too worse for wear, though, and Beckett looks—well, tired, but beautiful.

"Why'd you let me do that, Beckett?"

Beckett huffs. "I told you to take a break after the second shot," she points out with a perfectly arched brow and a smirk, and okay, that's something. He remembers the statement, but didn't realize it occurred after shots. Still, it's everything else that's screwing him up. She gestures to his coffee before she stands and makes her way toward the murder board. "Drink it, it'll help."

Save for just flat out asking if she was in his room last night, which he obviously can't do right now in the middle of the bullpen with Ryan, Espo, and a dozen other NYPD officers within earshot (and which he wouldn't do anyway, because he's a big chicken, might as well be covered in feathers), he's got nothing else.

Beckett's attention turns back for a split second to pick up her own coffee but she doesn't look at him, mind elsewhere already.

(She's right, though—the coffee helps.)

By the time they close the case (one involving a map coveted by hundreds of online treasure hunters which, Beckett was spot on, totally up his alley), he's nearly convinced everything he's remembered about that night was just a fever dream, an alcohol-clouded illusion. The memories (if he can even call them that at this point), the pills and water bottle—they mean nothing because Beckett hasn't brought any of it up.

And she would, he's sure of it.

Or, well, okay—maybe she wouldn't, because she doesn't exactly talk about things, but he's positive she'd at least be acting weird, a little squirrely around him. But she isn't.

And so he lets it go.

Beckett hasn't been acting strangely, there's been minimal to no change in their interactions (which he attributes mostly to his confused and slightly awkward contributions to conversation because he's still more than a little thrown off), and she hasn't alluded to there being any bad feelings or an elephant in the room.

Castle's not going to be the one to bring it up. If he did, there are only two ways it could go: his brain did, in fact, manufacture everything about the two of them spending the night together. He'll bring it up to Beckett and she'll look at him like he's certifiably insane and the floor won't be able to open up and swallow him fast enough. He'd have to leave the precinct and possibly New York.

On the other hand, perhaps it isn't a fabrication, perhaps they did have sex, and Beckett's silence is her way of choosing to ignore it. He'll bring it up and she'll have to tell him (in her quiet, slightly deer-in-the-headlights Beckett way) that it was great (because he can't imagine it being anything less than spectacular) but they should just carry on as they are now.

Or even worse, she hasn't said a thing because she regrets it. He'd choose being rejected a million times over if it meant that Beckett never has to be in that position.

It's settled then.

Based on fairly inconclusive evidence, and for the sake of his own sanity, Castle remains steadfastly in the camp of I Did Not Have Sex With Kate Beckett.